The present invention relates generally to railroad right of way maintenance machinery, and specifically to machinery used for forming and/or shaping rail track ballast in conjunction with railroad track repair, replacement or reconditioning.
Crushed rock rail ballast forms the support bed into which rail ties are inserted for receiving tie plates, spikes or other fasteners, and ultimately rail track. Ballast supports the weight of loaded trains, and also is sufficiently porous to remove standing water from the typically wooden ties. Also, the ballast provides the ability to maintain a constant rail/ground displacement or grading over varying terrain and soil conditions.
During railway maintenance operations, including but not limited to tie replacement, rail replacement or the like, the ballast becomes disrupted and must be reshaped. The optimal shape of rail ballast is a generally level upper surface in which the ties are embedded, and a pair of gradually sloping sides which flare out from ends of the rail ties at a specified angle or angular range which is generally constant across the railroad industry. However, depending on the application and available space, the angle of the ballast may vary.
To achieve the desired angular slope, self-propelled ballast regulators are employed, which feature at least one articulated, fluid-powered arm having at least one blade-like wing attached. Similar in function to a highway snowplow, the wing is oriented at a desired angle and is pushed by the ballast regulator through the ballast as the regulator moves along the track. To maximize the reuse of ballast stones dislodged during the regulation of the ballast, it is typical for an outer door to be provided with laterally oriented template doors. The template doors are pivotally connected to side edges of the outer door, and through the use of fluid-powered cylinders, the position of the template doors relative to the outer door can be adjusted to form “C-”, “U-” or similarly shaped configurations to retain a supply of disrupted ballast as the regulator moves along the track. In this way, there is sufficient ballast to fill in any depressions encountered to maintain a uniform slope.
In addition, an inner door is positioned generally parallel to the track between the outer door and template doors and the track to prevent ballast stones from falling on the rails or damaging the regulator itself during operational speeds in the range of 10-25 mph. Both the template door assembly and the inner door are typically mounted upon a boom which is pivotally joined to the regulator machine and is held in operational position by at least one fluid-powered cylinder.
One disadvantage of conventional rail ballast regulator wing assemblies, is that during operation, the wing assemblies often encounter debris or fixed objects such as culverts, concrete barriers, curbs, rails, concrete construction debris or the like. Moving at the speeds referred to above, the regulator template doors have a significant amount of momentum. Accordingly, when the moving template doors impact fixed obstacles, they often become damaged, misaligned, skewed or otherwise disfigured to the extent that the ballast reconditioning operation must be suspended until repairs can be made. Due to the remote nature of railway maintenance, repairs are often not easily made.
In some cases, crews arrange for temporary repairs in the field which are often unsatisfactory in the type of ballast reshaping achieved after repair, or in unwittingly increasing the wear and tear on other machine components due to imbalances or misalignments. In other cases, bent or destroyed template doors are replaced using available materials which do not always achieve desirable ballast reconditioning. A frequently damaged area is the hinge between the outer door and the template door, which if not repaired correctly, causes poor reconditioning or other operational problems. Another frequently damaged area is the pivot joint where the outer door is secured to the boom. This joint typically includes a solid pivot pin welded to a top plate which in turn is secured to an end of the boom. Strong impacts are often transmitted through the template door to the outer door, where they are focused on this pivot point. Pins and/or template doors become bent or cracked, and smooth pivoting action is prevented.
Thus, there is a need for an improved rail ballast wing assembly which can better withstand operationally induced impacts. There is also a need for an improved rail ballast template door which can withstand impacts and be easily repaired in the field to maintain desired operational performance characteristics. Further, there is a need for a rail ballast outer door pivot arrangement which can better withstand such operational impacts.